Synchronizing transmission



Nov. 8, 1932. P L, TENNEY 1,886,850

SYNCHIRBNIZING TRANSMISSION Original Filed July 17. 1929 2 Sheets-Sheet1 Zlwuentoz Nov. 8, 1932. P. L. TENNEY L SYNCHRONIZING TRANSMISSIONOriginal Filed July 17, 1929 2 Sheets-Sheet 2 Patented Nov. 8, 1932UNITED STATES PATEN'I} orrlcs rm! L. 1mm, 0] mom, INDIANA, ASBIGNOR '10GENERAL MOTORS CORPORA- T1011, 01' DETROIT, MICHIGAN, A CORPORATION OFDELAWARE SYNGDONIZIN'G TRANSMISSION Original application fled Iovmber 7,1981.

This invention relates to selective variable speed power transmittinggear mechanism for motor vehicles in which means are ut1- lized forbringing the intermeshable elements of high and intermediate speed trans to equal rates of speed before intermeshing, whlle low and reverseare selectively intermeshed in the usual manner.

This application is a division of apphcatlon Serial No. 378,910, filedJuly 17, 1929 and is directed to a selective shift mechanism adapted toselectively intermesh high and intermediate synchronized trains withagreater mechanical advantage than is apphed to intermeshnon-synchronized low and reverse and with the same amplitude of movementof the power arm of a manual shift lever.

In the drawings,

Fig. 1 is a longitudinal vertlcal sectlon through a motor vehicletransmlsslon mechanism embodying the inventlon;

Fig. 2 is a transverse section on l1ne 22 of Fig. 1, and

F' 3 is a longitudinal section through a frictlon clutch drum.

In the drawings, 5 indicates a gear box or casing enclosing the variablespeed elements of the transmission mechanism and having a detachablecover plate 6 from which rises a hollow, shift-lever-fulcrum support andhousing& A driving shaft 7, shown as the main clutch shaft of anautomobile, has ts rear end journaled in ball bearings 11 t front wall 9of the gear box. A gear 13 rlgiu with the rear end of shaft 7 within theear box is in constant mesh with gear 15 rlgid with counter shaft 17rotatable on a fixed shaft 19, the ends of which are supported in thefront and rear walls 9 and 21 of the gear box. Also rigid with thecounter shaft are intermediate speed train gear 23, low speed train gear25 and reverse train gear 27,

the latter intended to be in constant mesh with the usual reverse idlernot shown.

Also rigid with drive shaft 7 is a cupped ring-shaped composite clutchelement 29 equipped with internal gear-like clutch teeth 35 and anexternal conical friction clutch surface 33, merging into cylindricalsurface 31, said clutch element adapted to cooperate July 17, 1929,Serial No. 878,910. Divided and thil application flied Serial No.573,587.

end supported in ball bearing 39 in the rear wall of the gear box.

Intermediate-speed train spline-shaft gear 49 is journaled on hearingbushing 47 keyed to the spline shaft and prevented from moving axiallythereon b fastening rings 45 and 48. The bushing 4 has a flange integralwith it at the rear. Gear 49 is sleeved over.

said bushing, rearward movement being prevented by the rear flangethereon, while forward movement of said gear is prevented by a separatering flange at the front disposed between fastening ring 48 and thefront end of the bushing. Gear 49 is provided with external teeth 1nconstant mesh with the teeth of counter shaft gear 23 and may rotatefree- 1y about the spline shaft when the transmission is in neutral asillustrated in Fig. 1. Gear 49, is formed with a forward extendingannular part 59 formed internally with gearlike clutch teeth 64 andexternally with a conical friction clutch surface 62 merging into thecylindrical surface 60. Thus gear 49 is provlded with a compositefriction and positive clutch element which corresponds in size andcontour with, and faces the described composite clutch element 29 rigidwith the drive shaft. d

In order to selectively clutch spline shaft 37 to the drive shaft 7, toobtain high speed, or gear 49 to the spline shaft to obtain intermediatespeed, the following elements are use A double ended tooth clutchelement 61 is slidably splined to shaft 37 between the composite clutchelement 29 on the drive shaft and the composite clutch element 59integral with gear 49. External teeth 63 on one end of slidable clutchelement 61 may be meshed with'internal teeth 35 on companion clutchelement 29 rigid with shaft 7 to establish direct high speedconnections, and exelement 61 may be meshed with internal clutch teeth64 of companion clutch element 59 to establish intermediate speedconnections.

Gear wheel 51 slidably keyed to shaft 37 maybe slid forward to mesh itsteeth with the teeth of gear 25 rigid with the counter shaft toestablish low speed forward driving connection and may be slid rearwardto mesh its teeth with gear 27 on the counter shaft to procure reversedrive.

The axial extent of movement of gear 51 in order to mesh fully with gear25 or gear 27 is considerably greater than the axial extent of movementof slidable clutch element 61 to cause its teeth to interlock fully withcompanion clutch elements 29 and 59.

As more fully described in said parent application 378,910, in order topromote ease and quietness of speed changing, frictional devices areutilized for synchronizing the rotative speeds of shaft 37 and shaft 7before intermeshing teeth 63 of sliding clutch element 61 on shaft 37with the teeth of companion clutch element 29 on shaft 7; also for snchronizing the rotative speeds of shaft 37 and gear 49 beforeintermeshing teeth 65 of slidable clutch element 61 with teeth 64 ofcompanion clutch element 59 on gear 49. The frictional synchronizingdevice's comprise the frictional elements already described as formed oncomposite clutch element 29 rigid with shaft 7 and like compositeelement 59 formed rigid with gear 49, having the externally conicalsurfaces 33 and 62 respectively, and the respective cylindrical bearingsurfaces 31 and 60; and the double end companion friction element 85,consisting of a drum or barrel provided on the inside of its respectiveends with similar friction shoes 91, each having an internal conicalsurface cooperating with the companion surface on the respectivecompanion elements 29 and 59, and an internal cylindrical surfacebearing upon the appropriate external cylindrical surface of thecompanion member, whereby drum or barrel 85 tends to center in neutral.The drum is provided with longitudinal slots 97 having laterally ofi'setopposed V-shaped recesses 99 about midway of the slots. Radial arms 67on the toothed clutch element 61 have inclined faces on their endsprotruding into the slots 97. The ends of slides 55 and 74 hereillustrated as guided on parallel rods 57 and 75-fixed to the casing 5.Shifter slide 55, carries a yoke 53 arranged m engagement with a groovein a hub formed on gear 51, and couples low speed forward train whenmoved forward and reverse train when moved rearward. Shifter slide 74 isprovided with a yoke 73 engaged in an external groove 76 in ring 69, andwhen said slide 74 is moved forward, high speed train 1s coupled andwhen moved rearward intermediate speed train is coupled. Between the twoslides is disposed a locking rail 81 which is provlded with an automaticinterlocking device 83 of known type cooperating with the slides to lockone in neutral position during the operation of the other, and with anotch or gate 109 engageable by the lower end of the shift lever inneutral position in a known manner. Each slide carries a spring actuatedlatch 77 adapted to cooperate with notches in the rods on which they areguided, said latches serving to detain the slides in neutral and incoupling positions in a. manner well understood. The latch that isassociated with slide 74 is illustrated in Fig. 2. That associated withslide 55 is not shown but the casing for it is indicated at 54 Fig. 1.

To enable an operator to select and operate either shifter slide 55 or74 at will, a shift lever 101 of the first order, generically of knowntype, is universally pivoted at 119 within the hollow support 8. Thework arm of shift lever 101 is adapted to be selectively interlockedwith either shifter slide 55 or shifter slide 74, by means of devices tobe now described.

Shifter slide 55 has a notch 56 (indicated by dotted lines in Fig. 2)which in the neutral position is disposed in registration with notch orgate 109 in the fixed rail or rod 81. This notch 56, which is usual insliding gear transmissions, is of a depth equal at least to thetransverse thickness of the lower bearing terminus 117 of shift lever101. Shifter slide 74 is provided with an arm 111 rigid therewithextending upward and terminating with a bifurcated member 113 directedtoward the shift lever, the opening being in mg istration with thebearing formation 115, disposed between the fulcrum 119 and the terminus117 on lever 101, before mentioned, when said terminus 117 is seatedwithin the gate 109 as illustrated in the drawings. When the parts arein the neutral position illustrated terminus 117 projects slightly oneach slide of the fixed rail 81 into notch 56 of shifter slide 55, andinto a cut-away space 123 in slide 74, while the part 115 projectsslightly into the opening in the forked portion 113 of arm 111. Underthese conditions no fore and aft movement of shift lever can be madebecause the lower end of the shift lever is held by the gate in fixedrail 81.

In order to engage the low-speed-forward train the operator (sitting tothe rear of the shift lever,at the right as viewed in Fig. 1) seizes theupper end of the power arm 0 the shift lever and moves it to his left,thus moving the lower end of the lever to the right, fully engaging theterminus 117 on the work arm of the lever with the notch 56 in sl1de 55;then if the upper end of the lever is pulled 1 rearward, thus moving thelower arm forwhile intermediate part 115 enters fully into the space infork 113. Now movement of a the power arm of the shift lever forwardwill cause slide 74 to move rearward and shift clutch element 61 intoengagement wlth companion clutch element 59 on gear 49 thus couplingintermediate speed tram. Now moving the upper end of the shlft leverrearward will cause clutch element 61 to slide forward, disengage gear49 and engage cl utch element 29, thus coupling the transmission 1ndlrect high speed.

The extent of movement necessary to couple high and intermediate trains1s, as previously pointed out, less than that necessary to couple lowspeed and reverse trains and, as high and intermediate trams aresynchronized by friction clutches prior to belng positively coupled, aconsiderably greater force is necessary to obtain synchronization in thebrief time available than to shift the sliding gear of the low speed andreverse train. In the operating mechanism illustrated the gear 51, inorder to fully intermesh with one of its companion gears, has to travelfrom neutral about a distance of say one inch, while the clutch element61 in order to interlock with one of its companions has to travel fromneutral a distance of say one-half inch. The tip 117 and theintermediate part 115 of lever 101 travel in equal proportions (2: 1)and the length of the work arm engaging slide 55 to the length of thework arm engaging slide 74 is also about 2: 1. The power arm of theshift lever travels the same length of arc in making each shift. Byapplication of the same muscular force acting through the same distance,therefore, twice the force is transmitted to the slide that shifts thesynchronized coupling members, which need it, than that transmitted toshift the unsynchronized members which do not need it.

I claim: 4

1. In variable speed gear transmission mechanism, the combination of alow speed train devoid of'synchronizing devices and .a higher speedtrain associated with synchronizing devices, bothtrains includingshiftable coupling elements; a shifter slide connected to the shiftableelement of the low speed train, a shifter slide connected to theshiftable element of thehigher speed train, said last named slide havingan arm rigidly fixed thereto; a shift lever, means whereby the shiftlever ma arm, and means wliereby the shift lever may be interlocked withthe shifter slide that is connected to the low speed train at a pointfurther from the fulcrum of said shift lever than the-point ofconnection of the latter with said arm.

2. In variable speed gear transmission mechanism, the combination of alow speed train devoid of synchronizing devices and a higher speed trainassociated with synchronizing devices, both trains including shiftablecoupling elements; parallel guides, a shifter slide guided by one ofsaid guides and connected to the shiftable element of the low speedtrain, a shifter slide guided by the other of said guides, and connectedto the shiftable element of the higher speed train, said last namedshifter slide having an arm rigidly fixed thereto; a shift lever of thefirst order, means whereby the extremity of the work arm of the shiftlever may be interlocked with the shifter slide connected to theshiftable element of the low speed train, and means whereby the work armof the shift lever may be interlocked be interlocked with said with thearm of the slide connected to the higher speed train at a point betweenthe extremity of said work arm and the fulcrum of the shift lever.

3. In variable speed transmission mechanism, the combination of lowspeed and reverse trains, and high and intermediate speed trainsassociated with synchronizing devices, both trains including shiftablecoupling elements; a shifter slide connected to the shiftable element ofthe low and reverse trains, a shifter slide connected to the shiftableelements of the high andv intermediate speed trains, parallel guides forsaid slides disposed equidistant from the axis of the shiftableelements, and an arm rigidly secured to and rising from said'last namedslide; a shift lever, means whereby the work arm of the "shift lever maybe interlocked with the shifter slide connected to the shiftable'elementof low and reverse trains, and means whereby the work arm of the shiftlever may be interlocked with said arm rising from the shifter slideconnected to the high and intermediate speed train, at a point nearerthe fulcrum of the shift lever than the point of connection of saidlever to the low and reverse train.

4. In variable speed transmission mechanism, the combination of parallelshafts equipped with a low speed train including slidably meshed gears,a higher s (1 train including interengageable frictional and positiveclutch elements, a shifter slide connected to the slidable gear of thelow speed train, a shifter slide connected to the movable clutchelements of the hifher speed train and provided with a rigid y attachedarm extending at an an le to its path of movement, said clutch e ementshaving a shorter range of movement to and from engagement with theircompanion than the slidable gear of the low speed train; a shift leverof the first order, means whereby the extremity of the work arm of saidlever may be interlocked with the shifter slide connected with theslidable gear of the low speed train and means whereby the work arm ofsaid lever may be interlocked with said arm of the shifter slideconnected to the movable clutch elements of the higher speed train at apoint between the extremity of the work arm and the fulcrum of saidlever.

In testimony whereof I aflix my signature.

PERRY L. TENN EY.

